Examine source code of Game Library Checker

{
  "manifest_version": 3,
  "name": "Game Library Checker",
  "version": "1.11.0",
  "description": "Check if you own a game across Steam, GOG, and Epic. Shows GeForce NOW availability.",
  "icons": {
    "16": "icons/icon-brand.svg",
    "48": "icons/icon-brand.svg",
    "96": "icons/icon-brand.svg",
    "128": "icons/icon-brand.svg"
  },
  "permissions": [
    "storage",
    "menus",
    "activeTab",
    "scripting"
  ],
  "host_permissions": [
    "https://steamcommunity.com/*",
    "https://embed.gog.com/*",
    "https://www.epicgames.com/*",
    "https://store.epicgames.com/*",
    "https://accounts.epicgames.com/*",
    "https://store.steampowered.com/*",
    "https://static.nvidiagrid.net/*",
    "https://games.geforce.com/*"
  ],
  "background": {
    "scripts": [
      "lib/storage.js",
      "lib/matcher.js",
      "lib/steam-api.js",
      "lib/gog-sync.js",
      "lib/epic-sync.js",
      "lib/geforcenow.js",
      "background/background.js"
    ]
  },
  "action": {
    "default_popup": "popup/popup.html",
    "default_icon": {
      "16": "icons/icon-toolbar-dark-16.png",
      "32": "icons/icon-toolbar-dark-32.png"
    },
    "theme_icons": [
      {
        "light": "icons/icon-toolbar-light-16.png",
        "dark": "icons/icon-toolbar-dark-16.png",
        "size": 16
      },
      {
        "light": "icons/icon-toolbar-light-32.png",
        "dark": "icons/icon-toolbar-dark-32.png",
        "size": 32
      }
    ]
  },
  "options_ui": {
    "page": "options/options.html",
    "open_in_tab": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4dd075f4-fd27-45a3-b5b3-70eee007d109}",
      "strict_min_version": "120.0"
    }
  }
}